The Effects of Thermal and Atmospheric Pressure Radio Frequency Plasma Annealing in the Crystallization of TiO2 Thin Films

Abstract

Amorphous TiO2 thin films were respectively annealed by 13.56 MHz radio frequency (RF) atmospheric pressure plasma at discharge powers of 40, 60, 80 W and thermal treatment at its corresponding substrate temperature (Ts). Ts was estimated through three measurement methods (thermocouple, Newton’s law of cooling and OH optical emission spectra simulation) and showed identically close results of 196, 264 and 322 °C, respectively. Comparing with thermal annealing, this RF atmospheric pressure plasma annealing process has obvious effects in improving crystallization of the amorphous films, based on the XRD and Raman analysis of the film. Amorphous TiO2 film can be changed to anatase film at about 264 °C of Ts for 30 min plasma treatment, while it almost remains amorphous after 322 °C thermal treatment for the same time.